private function resizeMe(field:TextArea) :void

{

        field.validateNow();

        field.mx_internal::getTextField().autoSize = TextFieldAutoSize.LEFT;

        field.height = field.mx_internal::getTextField().height;

}

package com 

{

  import flash.events.Event;

  import flash.text.TextFieldAutoSize;

  import mx.controls.TextArea;

 

  public class AutoresizeTextArea extends TextArea 

  {

    public function AutoresizeTextArea() 

    {

      super();

      horizontalScrollPolicy = "off";

      verticalScrollPolicy = "off";

      this.addEventListener(Event.CHANGE, function(event:Event):void {

        invalidateSize();

      });

    }

 

    override protected function childrenCreated():void 

    {

      this.textField.autoSize = TextFieldAutoSize.LEFT;

      this.textField.wordWrap = false;

      super.childrenCreated();

    }

 

    override protected function measure():void 

    {

      super.measure();

      measuredWidth = textField.width;

      measuredHeight = textField.height;

    }

  }

}